apps/plugins/fft/kiss_fft.h

   1 #ifndef KISS_FFT_H
   2 #define KISS_FFT_H
   3
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <math.h>
   7 #include <string.h>
   8 /* no malloc
   9 #include <malloc.h>
  10 */
  11 #include "plugin.h"
  12 #include "lib/helper.h"
  13
  14 #ifdef __cplusplus
  15 extern "C" {
  16 #endif
  17
  18 /*
  19  ATTENTION!
  20  If you would like a :
  21  -- a utility that will handle the caching of fft objects
  22  -- real-only (no imaginary time component ) FFT
  23  -- a multi-dimensional FFT
  24  -- a command-line utility to perform ffts
  25  -- a command-line utility to perform fast-convolution filtering
  26
  27  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
  28   in the tools/ directory.
  29 */
  30
  31 #define KISS_FFT_MALLOC malloc
  32
  33
  34 #ifdef FIXED_POINT
  35 #include <inttypes.h>
  36 # if 1 /* 16-bit data is _slow_ on devices (FIXED_POINT == 32) */
  37 #  define kiss_fft_scalar int32_t
  38 # else
  39 #  define kiss_fft_scalar int16_t
  40 # endif
  41 #else
  42 # ifndef kiss_fft_scalar
  43 /*  default is float */
  44 #   define kiss_fft_scalar float
  45 # endif
  46 #endif
  47
  48 typedef struct {
  49     kiss_fft_scalar r;
  50     kiss_fft_scalar i;
  51 }kiss_fft_cpx;
  52
  53 typedef struct kiss_fft_state* kiss_fft_cfg;
  54
  55 /*
  56  *  kiss_fft_alloc
  57  *
  58  *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
  59  *
  60  *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
  61  *
  62  *  The return value from fft_alloc is a cfg buffer used internally
  63  *  by the fft routine or NULL.
  64  *
  65  *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
  66  *  The returned value should be free()d when done to avoid memory leaks.
  67  *
  68  *  The state can be placed in a user supplied buffer 'mem':
  69  *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
  70  *      then the function places the cfg in mem and the size used in *lenmem
  71  *      and returns mem.
  72  *
  73  *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
  74  *      then the function returns NULL and places the minimum cfg
  75  *      buffer size in *lenmem.
  76  * */
  77
  78 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
  79
  80 /*
  81  * kiss_fft(cfg,in_out_buf)
  82  *
  83  * Perform an FFT on a complex input buffer.
  84  * for a forward FFT,
  85  * fin should be  f[0] , f[1] , ... ,f[nfft-1]
  86  * fout will be   F[0] , F[1] , ... ,F[nfft-1]
  87  * Note that each element is complex and can be accessed like
  88     f[k].r and f[k].i
  89  * */
  90 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
  91
  92 /*
  93  A more generic version of the above function. It reads its input from every Nth sample.
  94  * */
  95 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
  96
  97 /* If kiss_fft_alloc allocated a buffer, it is one contiguous
  98    buffer and can be simply free()d when no longer needed*/
  99 #define kiss_fft_free free
 100
 101 /*
 102  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
 103  your compiler output to call this before you exit.
 104 */
 105 void kiss_fft_cleanup(void);
 106
 107
 108 /*
 109  * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
 110  */
 111 int kiss_fft_next_fast_size(int n);
 112
 113 /* for real ffts, we need an even size */
 114 #define kiss_fftr_next_fast_size_real(n) \
 115         (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
 116
 117 #ifdef __cplusplus
 118 }
 119 #endif
 120
 121 #endif